The invention is based on a fuel injection valve for internal combustion engines. One such fuel injection valve, known from German Offenlegungsschrift 43 40 883 A1, U.S. Pat. No. 5,497,947, has a valve body with an axial bore in which a pistonlike valve member is guided that is displaceable outward counter to the force of a closing spring to control an injection cross section by means of the fuel pressure. On its end toward the combustion chamber, the valve member has a closing head, which protrudes from the bore of the valve body and forms a valve closing member, and on whose side toward the valve body there is a valve sealing face, with which the closing head cooperates with a valve seat face disposed on the face end of the valve body toward the combustion chamber. At least one injection opening is also provided on the valve member, at the level of the closing head, which port originates at a pressure chamber formed between the valve member and the bore. The outlet opening of the injection opening is covered by the valve body in the closing position of the valve member and is not uncovered until the valve member emerges from the bore in the course of the outward-oriented opening stroke of the valve member.
With its end remote from the combustion chamber and remote from the closing head, the valve member protrudes into a spring chamber, which is formed in a retaining body braced axially against the valve body. On its shaft end remote from the combustion chamber, the valve member has a spring plate fastened to a closing spring between a stop solidly joined to the housing and contacting the valve body.
Fuel injection is effected with the onset of high-pressure fuel feeding into the combustion chamber of the injection valve; the high fuel pressure urges the valve member in the opening direction and lifts it away from the valve seat counter to the restoring force of the closing spring. Even after a short opening stroke motion of the valve member, the injection opening is opened, so that the fuel is injected into the combustion chamber of the engine to be supplied.
The opening stroke motion of the valve member is defined by the contact of a shoulder on the valve member shaft with a stop solidly joined to the housing; the maximum opening stroke can be adjusted via the location of this stop.
The known fuel injection valve has the disadvantage, however, that the opening stroke motion of the valve member is effected quite quickly because of the high fuel pressures, and so the valve member mechanically strikes the stop quite hard, engendering major mass forces at the valve member which under some circumstances can cause the valve member to break.
Moreover, in the known fuel injection valve, the course of the opening stroke of the valve member cannot be controlled, and hence shaping the course of injection of the injection valve, by way of which the injection and consequently the combustion in the combustion chamber can be varied, is not possible.